Using flexible-custom, I need to communicate with multiple regional databases including outside of our GCP netblocks, so we have a DNS VM with the appropriate entries as well as Cloud VPN. What I've found in practice is that Docker does not inherit the host's MTU (intentional, see moby <https://github.com/moby/moby/pull/18108> GitHub project for discussion), but neither does Docker do Path MTU Discovery on the bridge network correctly. This combines to mean that we have to manually set MTU lower on the container in order to not see packet fragmentation issues on the other end of our VPN link.
When I try and set MTU for a Debian container it seems rather difficult. App Engine doesn't seem to have a way to pass the Docker --mtu flag, and using ip link set dev eth0 mtu does work from SSH, but *seems* not to work if run as part of the container's CMD. Has anyone had to set MTU in App Engine for any reason and, if so, how do you get it to happen on startup and actually stick? -- You received this message because you are subscribed to the Google Groups "Google App Engine" group. To unsubscribe from this group and stop receiving emails from it, send an email to [email protected]. To post to this group, send email to [email protected]. Visit this group at https://groups.google.com/group/google-appengine. To view this discussion on the web visit https://groups.google.com/d/msgid/google-appengine/aed988a1-5929-4982-b38b-3f0966188a74%40googlegroups.com. For more options, visit https://groups.google.com/d/optout.
